This invention relates to a battery pack including a lower plate to hold battery module stacked members including stacked battery modules, and disposed in a plane.
A Published Japanese Patent Application Publication No. 2005-116440 shows a battery pack including stacked thin batteries (cells), or including battery module stacked members having stacked battery modules each having a plurality of stacked thin batteries. The stacked thin batteries or the battery module stacked members are arranged on a plate (hereinafter, referred to a lower plate) in a plane. Electric terminals of the thin batteries or electric terminals of the battery modules are electrically connected with each other.
In this battery pack, in a case of the lower plate made from a metal, the battery module stacked members may be unintentionally connected with each other (outer short-circuit) through the lower plate.
For improving this, it is conceivable that the lower plate is formed from insulative resin. However, in a case of the battery pack for the vehicle, there is necessary for large area. The lower plate made from the resin has a rigidity smaller than a rigidity of the lower plate made from the metal, and accordingly enough rigidity may not be ensured. In order to attain desired rigidity, the thickness of the lower plate is increased, and accordingly it is problematic to increase the weight and the size of the battery pack.